The most important annual release of the INSPIRE Reference Validator is scheduled for June 15, 2021. This release includes the validation rules applied in the end-of-year Monitoring process, i.e. the reference tests against which the conformity of the INSPIRE resources published by Member States are measured. In order to give NSDI entities and contractors sufficient time to prepare their sources for the monitoring deadline in December, each year the major release of the INSPIRE Reference Validator is published several months in advance (in June). In particular, any major changes (i.e. changes that make tests more restrictive as well as new tests) will be included in the version of the INSPIRE Reference Validator released on June 15, after which tests will not be more restrictive until annual monitoring in December. We kindly ask all NSDI entities as well as their contractors to test their resources that are harvested to the INSPIRE geoportal after the release of the new version of the Validator in order to start eliminating errors on time before the annual monitoring process in December.